Grinding mill or the like having reinforced shell and method of making same

ABSTRACT

A grinding mill or the like having a reinforced shell, and method of making same, including a shell formed of a cylindrical shell plate and having either radially outwardly or radially inwardly turned shell flanges. A cylindrical reinforcing plate is positioned contiguous each axial end of the shell plate and the corresponding shell flange to reinforce the shell in the high stress shell flange-shell plate region. The reinforcing plate or ring is integrally joined to the shell plate and to the shell flanges by a weld or welds, whereby the shell plate, the reinforcing ring members and the shell flanges form an integral structure.

United States Patent Appll No. Filed Patented Assignee GRINDING MILL OR THE LIKE HAVING REINFORCED SHELL AND METHOD OF MAKING SAME 8 Claims, 4 Drawing Figs.

US. Cl 241/179, 29/47 1 1, 220/71 Int. Cl B02c 17/18 Field of Search 220/71;

29/47l.l;24l/l79, 180, 181, 182, 183,91

Primary ExaminerDonald G. Kelly Att0rneysRobert C. Sullivan, Arthur M. Streich and Robert B. Benson ABSTRACT: A grinding mill or the like having a reinforced shell, and method of making same, including a shell formed of a cylindrical shell plate and having either radially outwardly or radially inwardly turned shell flanges. A cylindrical reinforcing plate is positioned contiguous each axial end of the shell plate and the corresponding shell flange to reinforce the shell in the high stress shell flange-shell plate region. The reinforcing plate or ring is integrally joined to the shell plate and to the shell flanges by a weld or welds, whereby the shell plate, the reinforcing ring members and the shell flanges form an integral structure.

IIIIIIIIIA PATENTEU JAN26 ssn a p/ MAM? GRINDING MILL OR THE LIKE HAVING REINFORCED SHELL AND METHOD OF MAKING SAME BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to grinding mills or the like such as ball or tube mills or the like and more particularly to an improved shell construction for such grinding mills or the like.

2. Description of the Prior Art Grinding mills of the type presently being constructed in accordance with current manufacturing methods comprise a cylindrical shell having oppositely disposed welded end flanges integrally connected thereto, and oppositely disposed end plates which are bolted to the respective end flanges. In the case of grinding mills, the end plates carry oppositely disposed hollow trunnions for the feed and for the discharge, respectively, of the material being ground in the mill. The integrally connected end flanges at the opposite ends of the cylindrical grinding mill shell may extend either radially outwardly (the usual standard type) or may extend radially inwardly of the cylindrical shell.

In either of the types of flange connections just mentioned, that is, the radially outwardly extending flange and the radially inwardly extending flange, the region of the junction between the cylindrical shell and the shell flange is a region of high stress.

SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provide a grinding mill or the like having a shell which is reinforced in the high stress junction region of the shell plate and the shell flange.

It is another object of the invention to provide a method of manufacturing a reinforced shell for a grinding mill or the like.

It is still another object of the invention to provide a method of manufacturing a reinforced shell for a grinding mill or the like which is adapted for use with shells of either the radially outwardly turned shell flange type or of the radially inwardly turned shell flange type.

In achievement of these objectives, there is provided in accordance with this invention a grinding mill or the like having a cylindrical shell formed of a cylindrical shell plate and having either radially outwardly or radially inwardly turned shell flanges with an annular reinforcing ring member being positioned contiguous each of the axially opposite ends of the shell plate and the corresponding shell flanges, whereby to reinforce the shell in the high stress junction region of the shell plate and the shell flanges. The reinforcing ring is integrally joined to the shell plate and to the shell flanges by a weld or welds, whereby the shell plate, the reinforcing ring members, and the shell flanges form an integral structure having greatly reduced stress in the critical junction regions of the shell plate and shell flanges.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings in which;

FIG. I is a view in longitudinal section, partially cut away, of a grinding mill or the like having the reinforced construction in accordance with the invention, the shell being of the type having radially inwardly turned shell flanges;

FIG. 2 is an enlarged fragmentary view of the welded connection between the shell plate, the reinforcing ring or plate, and the shell flange;

FIG. 3 is a view similar to FIG. I of a grinding mill or the like having the reinforced construction of the invention, the shell being of the type having radially outwardly turned flanges; and

FIG. 4 is a fragmentary view in longitudinal section of a modified embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a grinding mill generally indicated at comprising a shell generally indicated at 12 and end plates 14 and 16, respectively. The oppositely disposed end plates 14 and I6 carry hollow trunnions l8 and 20, respectively, which are supported for rotation be bearings (not shown) whereby the grinding mill is mounted for rotation upon the bearings by means of the trunnions I8 and 20.

The shell generally indicated at 12 includes a cylindrical shell plate 22 and oppositely disposed radially inwardly turned end flanges 24 and 26, respectively. The shell flange 26 includes a portion 27 which cxtends'radially outwardly beyond the periphery of cylindrical shell plate 22 for attachment to a gear. The radially outer ends of the end plates 14 and I6 terminate in flange portions 28 and 30, respectively, which are suitably secured, as by bolts or the like, to the radially inner ends of the shell flanges 24 and 26.

In accordance with the invention, a hollow cylindrical reinforcing ring each indicated at 32 is interposed between each axially outer end of the shell plate 22 and the contiguous shell flange 24 or 26. The reinforcing rings 32 are of greater radial thickness than the thickness of the shell plate whereby to provide an increased radial wall thickness in the critical stress region between the axial ends of the shell plate and the con tiguous shell flanges 24 and 26. In the illustrated embodiment, the reinforcing rings 32 have the radially inner surface thereof flush with or of the same internal diameter as the radially inner surface of cylindrical shell plate 22, but have a greater outer diameter than the outer diameter of shell plate 22, due to the greater radial thickness of reinforcing rings 32 as compared to the radial thickness of shell plate 22.

As best seen in the enlarged view of FIG. 2, a substantially fully penetrated weld 34 is positioned between shell flange 24 and reinforcing ring 32. Weld 34 is received in a region of triangular cross section defined by chamfered edges 36 and 38 on shell flange 24 and on reinforcing ring 32 respectively. Also a substantially fully penetrated weld indicated at 40 is positioned between the reinforcing ring 32 and the shell plate 22. In the illustrated embodiment, the chamfered edges 42 and 43 on the reinforcing ring 32 cooperate with the chamfered edges 44 and 45 on the shell plate 22 to define weld receiving re gions which merge into a single fully penetrated weld 40 during the welding operation. Also a fillet weld 46 is preferably made between the radially inner surface of each reinforcing ring 32 and the contiguous surface of flange 24, and of flange 26, respectively.

There is shown in FIG. 3 a grinding mill of the type having a shell with a radially outwardly turned flange. The grinding mill of FIG. 3 is generally indicated at 50 and comprises a shell generally indicated at 52 including a cylindrical shell plate 54 having oppositely disposed radially outwardly turned shell flanges 56 and 58 at the opposite axial ends thereof. A hollow cylindrical reinforcing ring or plate 60 is axially interposed between the cylindrical shell plate 54 and each of the respective shell flanges 56 and 58 in a manner similar to that shown in FIG. 1, each cylindrical inserted reinforcing plate 60 being secured to the axially endmost edge of the shell plate 54 and to the respective shell flanges 56 and 58 by substantially fully penetrated welds 61 and 63 as described in the case of the embodiment of FIG. I. A fillet weld 65 is preferably made between the radially outer surface of each reinforcing ring 60 and the contiguous surface of flange 56 or 58. The grinding mill 50 also includes end plates generally indicated at 62 and 64 at the inlet and discharge ends of the grinding mill, respectively. Each of the respective end plates 62 and 64 induces a hollow trunnion indicated at 66 and 68, respectively. The hollow trunnions are supported by suitable bearings (not shown) which support the grinding mill for rotation. Each of the end plates 62 and 64 is also provided with a radially outer flange portion indicated at 70 and 72, respectively, the flange portions 70 and 72 being bolted or otherwise suitably secured to the shell flanges 56 and 58 respectively.

In each of the illustrated embodiments of FIGS. I and 3, the hollow cylindrical reinforcing ring or plate 32 (FIG. 1) and 60 (FIG. 3) is of greater radial thickness than the radial thickness of the shell plate 22 or 54 to which it is weldedly secured. The reinforcing shell plates 32 and 60 both reduce stress in the respective shells l2 and 52 in the critical stress region adjacent the junction of the shell plate and the shell flange at each end of the shell.

There is shown in FIG. 4 a modified embodiment of the invention in which the reinforcing ring, rather than being axially interposed between the shell plate and the shell flange as in the embodiments of FIGS. l-3, inclusive. is rather positioned in radially superposed coaxial relation to the cylindrical shell plate.

Referring now to FIG. 4, there is shown a fragmentary view of one end of a grinding mill or the like including a shell generally indicated at 12'. The shell 12 comprises a cylindrical shell plate 22' which directly abuts against the radially inwardly extending shell flange 24' at each end of the shell and is welded thereto. The grinding mill also includes end plates 14' each having an integral trunnion l8 and an integral flange 28 which is bolted to the radially inner end of the corresponding shell flange 24'. In accordance with this embodiment of the invention, a reinforcing ring 80 overlies the radially inner surface of shell plate 22 contiguous the junction of the shell plate 22' and the shell flange 24', abutting both the shell plate and shell flange. The reinforcing ring 80 is suitably welded as indicated at 82 and 84 to the shell plate 22' and to the shell flange 24', respectively. The use of the reinforcing ring 80 which is rigidly attached by welding to both the shell plate 22 and to the shell flange 24', as just described, reduces the stress in the critical region adjacent the junction of the shell plate and the shell flange. A similar reinforced construction is provided at each end of the shell 12.

While the reinforcing ring 80 in FIG. 4 has been shown in superposed coaxial relation to the radially inner surface of shell plate 22, it could instead be coaxially positioned about and rigidly secured by welding to the radially outer surface of shell plate 22' and to the contiguous shell flange.

In all of the various embodiments of FIGS. l4, the required dimensions and geometry of the reinforcing plate or ring for a given mill shell will be determined by means of stress analysis of the shell flangeshell plate region of the shell.

From the foregoing detailed description of the present invention, it has been shown how the objects of the invention have been attained in a preferred manner. However, modifications and equivalents of the disclosed concepts such as readily occur to those skilled in the art are intended to be included within the scope of this invention.

1 claim:

1. A grinding mill comprising a shell including a hollow cylindrical shell plate, a shell flange at an axial end of said shell. and a reinforcing ring axially interposed between and rigidly welded both to said shell flange and to said shell plate whereby to reinforce said shell in the high stress region at the axial end of said shell.

2. A grinding mill as defined in claim I in which said reinforcing ring is welded to said shell flange and to said shell plate by substantially fully penetrated welds.

3. A grinding will as defined in claim 1 in which said reinforcing ring is of greater radial thickness than said shell plate.

4. A shell for a grinding mill comprising a hollow cylindrical shell plate, a shell flange at an axial end of said shell, and a reinforcing ring axially interposed between and rigidly welded both to said shell flange and to said shell plate whereby to reinforce said shell in the high stress region at the axial end of said shell.

5. A shell for a grinding mill as defined in claim 4 in which said reinforcing ring is welded to said shell flange and to said shell plate by substantially fully penetrated welds.

6. A shell for a grinding mill as defined in claim 4 in which said reinforcing ring is of greater radial thickness than said shell plate.

7. A method of making a shell for a grinding mill of the type comprising a hollow cylindrical shell plate extending axially of said shell and a shell flange at an axial end of said shell which comprises the step of rigidly welding to both said shell plate and to said shell flange and in axially interposed relation between an axial end of said shell plate and said shell flange a hollow cylindrical reinforcing ring of greater radial thickness than said shell plate, whereby to reinforce said shell in the high. stress region between said shell plate and said shell flange.

8. A method of making a shell as defined in claim 7 in which the step of rigidly joining said hollow cylindrical reinforcing ring to said shell plate and to said shell flange comprises wcld ing said ring to said plate and to said flange by substantially fully penetrated welds whereby said ring, said plate, and said flange become an integral structure. 

1. A grinding mill comprising a shell including a hollow cylindrical shell plate, a shell flange at an axial end of said shell, and a reinforcing ring axially interposed between and rigidly welded both to said shell flange and to said shell plate whereby to reinforce said shell in the high stress region at the axial end of said shell.
 2. A grinding mill as defined in claim 1 in which said reinforcing ring is welded to said shell flange and to said shell plate by substantially fully penetrated welds.
 3. A grinding mill as defined in claim 1 in which said reinforcing ring is of greater radial thickness than said shell plate.
 4. A shell for a grinding mill comprising a hollow cylindrical shell plate, a shell flange at an axial end of said shell, and a reinforcing ring axially interposed between and rigidly welded both to said shell flange and to said shell plate whereby to reinforce said shell in the high stress region at the axial end of said shell.
 5. A shell for a grinding mill as defined in claim 4 in which said reinforcing ring is welded to said shell flange and to said shell plate by substantially fully penetrated welds.
 6. A shell for a grinding mill as defined in claim 4 in which said reinforcing ring is of greater radial thickness than said shell plate.
 7. A method of making a shell for a grinding mill of the type comprising a hollow cylindrical shell plate extending axially of said shell and a shell flange at an axial end of said shell, which comprises the step of rigidly welding to both said shell plate and to said shell flange and in axially interposed relation between an axial end of said shell plate and said shell flange a hollow cylindrical reinforcing ring of greater radial thickness than said shell plate, whereby to reinforce said shell in the high stress region between said shell plate and said shell flange.
 8. A method of making a shell as defined in claim 7 in which the step of rigidly joining said hollow cylindrical reinforcing ring to said shell plate and to said shell flange comprises welding said ring to said plate and to said flange by substantially fully penetrated welds whereby said ring, said plate, and said flange become an integral structure. 